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authorMikulas Patocka <mpatocka@redhat.com>2021-05-07 18:38:10 +0300
committerMike Snitzer <snitzer@redhat.com>2021-05-10 18:11:36 +0300
commit7ee06ddc4038f936b0d4459d37a7d4d844fb03db (patch)
tree031bf1397372f0c2f2d3180e16619578387f1c75 /drivers/md
parent6efb943b8616ec53a5e444193dccf1af9ad627b5 (diff)
downloadlinux-7ee06ddc4038f936b0d4459d37a7d4d844fb03db.tar.xz
dm snapshot: fix a crash when an origin has no snapshots
If an origin target has no snapshots, o->split_boundary is set to 0. This causes BUG_ON(sectors <= 0) in block/bio.c:bio_split(). Fix this by initializing chunk_size, and in turn split_boundary, to rounddown_pow_of_two(UINT_MAX) -- the largest power of two that fits into "unsigned" type. Reported-by: Michael Tokarev <mjt@tls.msk.ru> Tested-by: Michael Tokarev <mjt@tls.msk.ru> Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-snap.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index a2acb014c13a..2a51ddd840b4 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -855,12 +855,11 @@ static int dm_add_exception(void *context, chunk_t old, chunk_t new)
static uint32_t __minimum_chunk_size(struct origin *o)
{
struct dm_snapshot *snap;
- unsigned chunk_size = 0;
+ unsigned chunk_size = rounddown_pow_of_two(UINT_MAX);
if (o)
list_for_each_entry(snap, &o->snapshots, list)
- chunk_size = min_not_zero(chunk_size,
- snap->store->chunk_size);
+ chunk_size = min(chunk_size, snap->store->chunk_size);
return (uint32_t) chunk_size;
}